Apparatus for obtaining ammonia.



' Patontod Ian. 29 I901.

H. FISCHER APPARATUS FOR OBTAINING AMMONIA.

Application filed. Aug. 8, 1899.) y

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UNITE STATES ATENT' APPARATUS FOR OBTAINING AMMONIA.

SPECIFICATION-forming part of Letters Patent No. 666,657, dated. January 29, 1901.

Application filed August 8. 1899. e'erial No. 726,545. (No model.)

To all whom, it may concern:

Be it known that I, HEINRICH FISCHER, managing director, of Peek, Bohemia, in the Empire of Austria-Hungary, have invented certain new and useful Tmprovements in Apparatus for Obtaining Ammonia and its Salts from the Spent Liquor of Molasses in Sugar Factories and from Vinasse, of which the fol lowing is a specification.

The process for which my apparatus is adapted is as follows: The alkaline vinasse or Waste liquor which has been rendered thick by evaporation or by the action of carbonic acid and freed from lime, strontium, or baryta in the usual manner is introduced in the evaporating-chamber of the kiln into vessels provided with an agitator and heated by the hot gases from the distillation-chamber and is then evaporated to nearly complete anhydrous concentration without exceeding a temperature of 200 centigrade. The concentrated vinasse is then passed through a conduit furnished with a heating-jacket and into a gasifying-retort proper. The retortsare of channel form and are provided with an agitating-screw. This latter by a simple device can be transformed into a conveyor-screw; but during the mixing operation it is caused to slowly make a revolution first in the one and then in the other direction and so effectually and continuously to keep the vinasse agitated during the gasifyin g operation. The retorts are formed in batteries in a kiln according to the amount of vinasse to be treated. The retorts at starting are heated by means of coal; but as soon as the kiln produces acontin uous current of gas the latter is used as the heating agent. Each retort is provided with a separate gas-furnace with regulating slide or valve for the gas and air, enabling the temperature in the interior of the retort to be elevated to any desired degree. The temperature is allowed to rise slowly from 200 to 500 centigrade. The operation is watched by taking samples from time to time from the retort, and at the end of the operation when the sample proves the gasification to be complete the retort is discharged. To this end the agitating-screw is caused to rotate in one direction only, and thus acts as a conveyerscrew for discharging the retort after having previously opened the slide-door of the same.

- conveyer-screw 2.

After having discharged the retort it is recharged With vinasse, as before, and the process repeated. The gases evolved from the vinasse during evaporation and distillation are driven either by its own pressure or by means of an exhauster into a receiver, .Where the largest portion of the tar collects. From this receiver the gases pass through tube-condensers similar to those in use in connection with cokekilns for the extraction of ammonia, and after separating out the largest portion of the distillation products they pass into the gasometer, from which separate pipes lead to the-gas-furnaces of the retorts. In this manner fine calcinated vinasse is obtained possessing sufficient temperature to burn to white ash on the heap. Beyond this there is obtained about four per cent. of ammoniacal liquor, together with the usual products of distillation, tar, and nicely-burning highlyheat-giving gas. The ammoniacal liquor is collected in reservoirs, filtered, and is then treated for ammonia or salts in the ordinary manner. The tar mixed with coal-dust forms an excellent combustible. The combustion-gases from the retorts pass underneath the evaporating vessels and thence into the chimney.

The chief consideration in this process is the correct maintenance of temperature, not

exceeding 600 centigrade, together with constant and thorough stirring of the material, as on this depends the fullest possible yield in ammonia products. At higher temperature complex products of distillation are formed, while ammonia decomposes and forms nitrogen, and at a still higher temperature it forms cyanogen.

The apparatus for carrying out the above process is shown in the accompanying drawings, in which- Figure 1 is a front elevation, partlyin section, on the lines A B and O D of Fig. 2. Fig. 2 is a longitudinal section of the apparatus, and Fig. 3 is an elevation of the reversinggear for the agitator.

The gutter-like retorts l are combined in the form of a battery of a certain number in one kiln, and each retort is provided with a The retorts are advantageously closed permanently at one end and are furnished attheir other and open end with a door 3, operated by a toothed pinion 4 and rack 5. At this end also is provided a pyrometer 6 for ascertaining the temperatures.

Below each retort is a primary furnace 7, by which the retorts are first heated till enough gas has been produced from the distillation to serve in heating the retorts. For this purpose a gas-supply pipe 8, in connection with the gasonieter, is arranged along the front of the kiln, and from this general supply-pipe a separate branch pipe leads into the nozzle 9 and is adapted to be closed bya valve 10. The gas-hearth consists of a channel 11 of refractory clay and having a number of openings 12 for the gas-jets. The air for combustion enters through a regulated slide 13- The combustion products pass alongthe flue14 and thence through fine 15 into the chimney. In order to allow of any one of the retorts being disconnected for discharging or other purposes, a damper or slide 16 is so disposed as to close the flue 14 from the main flue 15. The gases evolved by this dry distillation pass, either under their own pressure or through the action of an exhauster, along a pipe 17 into a receiver 18, where the tar separates, while the remaining gases pass through a pipe 19 into the condenser, from which only the gases for combustion are allowed to pass into the gasometer. With a view of completely utilizing the combustion products it is advantageous to build the evaporating vessels 20 into the flue 15, as shown, so as to evaporate the vinasse.

The motion for the screwa reciprocating rotary or a continuous motion-may be obtained by means of any known contrivance; but for completeness of the specification the mechanism shown in Fig. 3 has been adopted. This mechanism consists of a Worm-wheel 21, keyed on the shaft of the screw 2 and actuated by a worm 22. On the shaft of this worm are mounted a fast pulley 23 and two loose pulleys 24 25, supplied with a straight and with acrossed belt adapted to be shifted by a belt-shifting fork 26. The shifting-fork is advantageously operated through the intervention of a compressed-air piston moving in a cylinder supplied alternately from the right and from the left with compressed air. The reversing operation for the piston is effected bya three-way cook 27, the operation-lever 28 of which is in the path of a tappet 29, provided onthe worm-wheel, which on being revolved reverses the cock-valve 27 and causes the compressed air'which enters at 30 to pass through the one or the other branch 32 to the cylinder which exhausts into the atmosphere. When it is desired to provide a continuous rotation for the conveyerscrew 2, it suffices to remove the lever 28 of the cock-valve 27 from the path of the tappet 29.

Having now particularly described and ascertained the nature of my said invention, I declare that what I claim is- In combination, the retort, the screw therein, gearing connected with the screw and shaft, belt-pulleys for operating the gearing in either direction, and automatic means for shiftingthe belt comprising the shifting-fork, a cylinder and piston, a supply-pipe leading to the piston, a cock controlling the supply to either end of the cylinder and a projection or part of the gearing for operating the cock.

In witness whereof I have hereunto set my hands in presence of two witnesses.

. HEINRICH FISCHER.

Witnesses:

ALVESTO S. HOGUE, AUGUST FUGGER. 

